Heather Fong, a 26-year veteran of the San Francisco Police Department who has been acting chief since January, will be named to the top spot permanently, Mayor Gavin Newsom said Monday.

Fong, 47, will be the first woman to lead the department in the city's history if the Police Commission confirms her selection Wednesday, as expected.

"Change is now under way," Newsom said at a news conference at the Hall of Justice, in which he also addressed the slaying over the weekend of Officer Isaac Espinoza. "It's a new administration. It's a new day in San Francisco. There's a new resolve to do things differently."

Newsom said he had planned to name Fong to the job on a permanent basis Sunday but delayed doing so because of the killing.

The announcement, which usually would create a congratulatory atmosphere, was muted by Espinoza's death. Pictures of the 29-year-old officer were posted around the room.

"This comes at a time of great grief and sorrow," Fong said after the mayor introduced her.

Fong, who is known for her quiet demeanor, said nothing else about her appointment. Instead, she spoke of the measures she is putting in place to try to quell gun violence in Bayview-Hunters Point, where Espinoza was killed Saturday night.

They include staffing the Bayview and Ingleside stations with more officers, meeting with faith-based organizations and performing community outreach.

"Hopefully, the youth of today will not continue in this trend of violence," Fong said.

Fong became acting chief after Newsom moved former Chief Alex Fagan to head the city's Office of Emergency Services. Fong also served briefly as acting chief last year when Fagan, former Chief Earl Sanders and eight other members of the department were indicted in connection with an alleged street assault involving three off-duty officers.

Charges against Sanders, Fagan and the other officers not directly involved in the incident were quickly dismissed.

This year, the city paid $25,000 to Bob Murray and Associates to conduct a national search for a chief, which yielded 43 applicants. Of those, the firm picked 11 candidates for consideration.

Former Police Chief Fred Lau, who recruited Fong for the department in 1977, agreed.

"I couldn't be happier," Lau said. "He could have gone all over the world, and he couldn't find anyone better."

Lau called the promotion well-deserved and well-earned.

"Because of her demeanor and her professionalism, she'll bring back the stability that the department needs at this time," Lau said.

With Fong's appointment, San Francisco joins three other large cities that have chosen women in the past year to head their police departments. The others are Boston, Detroit and Milwaukee.

Fong will earn a salary in the range of $210,000.

A North Beach native, Fong grew up as the younger of two sisters who attended Roman Catholic schools. Her family lived near Lau, who later became her mentor.

Fong's father died several years ago. Her mother, Mabel, has long worked for a prominent Chinatown law firm as a legal secretary.

Fong graduated from the University of San Francisco, where she was a member of the Air Force ROTC. She also worked as a police cadet while in college.

After joining the force at age 21, she earned a master's degree in social work from San Francisco State University.

Fong, who is fluent in Cantonese, served as a liaison to the Chinese community during her early years in the department. She rose steadily through the ranks and in 1994 was among the first three women to be named captain.

Under Lau, Fong ran the patrol division, but Sanders moved her to the lower-profile post of deputy of administration.

"She's worked harder than anyone I know," Lau said. "The community's going to benefit. The department's going to benefit."